Standard UIAA/CE "single" rope, 50 meter if you are only going to have 2 people. You can get away with a 50m "double" or "half" under some circumstances. I sure hope you already know how to do crevasse rescue with just 2 people - it isn't easy. Of course, if you knew how already, you wouldn't have asked the question.

You would also know that you tie the 2 of you in about 10-15 meters apart, about 15-20 meters in from the ends of the rope, with the spare ends on your shoulder in a kiwi coil or mountaineer's coil, and you would already know that you need your prussick or ascender setup on the rope in advance, as well as how to rig a C or C-Z to haul your partner out of the slot.

If this is not something you know already, you better sign up for a couple courses with a professional instructor. There are some little tricks of the trade that make a big difference between success and the death of your partner (or you or both) that you can't learn from a book or a video.

I would strongly suggest you do not go out on a glacier trip unless you are doing so with someone who has many such trips under their belt. There are so many ways to get hurt or killed on the ice. Even if you learn all of them it takes practice under a watchful eye to be reminded of your oversights before this stuff becomes second nature. For example people often travel safely but let down their guard while on a rest break, causing the leader to fall because they were not belayed out of the rest stop. Or on a similar vein, groups sometimes forget to probe the camp area or mark the boundaries of the camp area, resulting in an unroped fall. And then there is the issue of all those sharp points on your boots and tools that can gore you when panic causes you to flail. Lastly no amount of flat lander practice will prepare you for crevasse rescues on the real thing. The wise trekker will spend several days around real crevasses learning this skill under skilled supervision, before striking off into the Great Wild. Basic Mountaineering courses do not adequetly prepare you to go off on glaciers on your own. Even the pros practice rescues frequently, such is the difficulty and danger of crevasses.